Create an MP4 only when needed
MTS is commonly used for AVCHD camera video, while MP4 is a broadly supported delivery container. Conversion is useful when a player, service, or device cannot use the original stream, but it is not required when the source already works.
Use H.264 with AAC for broad compatibility, retain the source dimensions and frame rate where possible, and test picture, motion, audio, and sync. Because video may be re-encoded, avoid promising identical source quality.
Guide topic preview

